CS 3451 INTRODUCTION TO OPERATING SYSTEM

QUESTION BANK
UNIT 1 - INTRODUCTION
PART-A
1. List and briefly define the four main elements of a computer?
2. Define the two main categories of processor register?
3. In general terms, what are the four distinct actions that machine instruction can specify?
4. What is an Interrupt?
5. How are multiple interrupt dealt with?
6. What characteristics distinguish the various elements of a memory hierarchy?
7. What is Cache Memory?
8. List and briefly define 3 Techniques of I/O operation?
9. What is the distinction b/w spatial locality & temporal locality?
10. Define Locality of Reference
11. What is an operating system?
12. What are the 3 objective of an OS Design?
13. List the Services of operating system function.
14. Define Kernel
15. Define system call.
16. What is System Programs?
17. What is Boot strapping?
18. Difference b/w Monolithic & Microlithic.
19. What is Multiprogramming?
20. Define Real Time System.
21. What does the CPU do when there are no user programs to run?
22. What is multicore processor?
23. What is memory stall?
24. What is Boot strapping?
25. Compare and contrast DMA and cache memory.
26. What is the purpose of system programs?
27. What are the advantages of peer-to-peer systems over client-server systems?
28. Write the difference between Batch systems and Time sharing systems.
29. Why API s need to be used rather than system calls?
30. Do timesharing differ from Multiprogramming? If so, How?
 PART – B
1. Explain Operating System Structure and components.
2. Discuss multiprocessor systems in detail.
3. Explain in detail the types of system calls provided by a typical operating system.
4. Explain the purpose of system calls and discuss the calls related to device management
and communications in brief.
5. Explain the concepts of virtual machines, their implementation and benefits in details.
6. What is a virtual machine? List out the advantages of virtualization. Explain the
creation of a Virtual machine with a architecture diagram
7. Write short notes on operating system services and components.
8. Write in detail about the real time system and multiprocessor system.
9. Write in detail about hardware protection.
10. Explain the various types of System calls with an example for each?
11. Discuss about the functionality of system boot with
respect to operating system.
12. Discuss about the evolution of virtual machines. Also explain how virtualization could
be implemented in operating systems.
13. Sketch the structure of Direct Memory Access in detail.
14. With neat sketch discuss computer system overview
15. Enumerate the different operating system structure and explain with neat sketch.
16. State the basic functions of OS and DMA.
17. Explain system calls, system programs and OS generation.
18. Distinguish between the client-server and peer-to-peer models of distributed systems.
19. Describe three general methods for passing parameters to the operating system with example.
20. How could a system be designed to allow a choice of operating systems from
which to boot? What would the bootstrap program need to do?
21. Describe the differences between symmetric and asymmetric multiprocessing. What
are three advantages and one disadvantage of multiprocessor systems?

UNIT II - PROCESS MANAGEMENT

 PART-A
1. Define Process?
2. Draw & briefly explain the process states?
3. What is process control block? List out the data field associated with PCB.
4. What is meant by context switching?
5. Define co- operating process and independent process.
6. What are the benefits of multithreaded programming?
7. What is a thread?
8. Under What circumstances CPU scheduling decision takes place.
9. What are the various scheduling criteria for CPU scheduling?
10. Define busy waiting and spinlock.
11. What is mean by monitors?
12. What are the characterizations of deadlock?
13. Differentiate a Thread form a Process.
14. What are the difference b/w user level threads and kernel level threads?
15. What is the use of fork and exec system calls?
16. Define thread cancellation & target thread.
17. What is critical section problem?
18. What are the requirements that a solution to the critical section problem must satisfy?
19. Define mutual exclusion.
20. What is semaphore? Mention its importance in operating system.
21. Define CPU scheduling.
22. What is preemptive and nonpreemptive scheduling?
23. What is a Dispatcher?
24. Define the term ‘dispatch latency’?
25. Define throughput?
26. What is turnaround time?
27. Define race condition.
28. Define deadlock.
29. What is a resource-allocation graph?
30. What are the methods for handling deadlocks?

PART-B
1. Explain the FCFS, preemptive and non-preemptive versions of Shortest-Job First and Round
Robin (time slice = 2) scheduling algorithms with Gantt charts for the four Processes given.
Compare their average turnaround and waiting time.
Process Arrival Time Waiting Time
P1 0 8
P2 1 4
P3 2 9
P4 3 5
2. Discuss how scheduling algorithms are selected for a system. What are the criteria
 considered? Explain the different evaluation Methods.
3. Write in detail about several CPU scheduling algorithms.
4. What is critical section? Specify the requirements for a solution to critical section problem.
5. How monitors help in process synchronization
6. Write in detail about deadlock avoidance.
7. Write in detail about deadlock recovery.
8. Explain the Banker algorithm for deadlock avoidance in detail with an example.
9. Consider the following set of processes, with the length of the CPU – burst time given in
Milliseconds:
Process Burst Time Priority
P1 10 3
P2 1 1
P3 2 3
P4 1 4
P5 5 2
The processes are arrived in the order P1, P2, P3, P4, P5, all at time 0.
1. Draw 4 Gantt charts illustrating the execution of these processes
using FCFS, SJF Priority and RR (Time Slice = 1) scheduling
2. What is the turnaround time of each process for each of the scheduling?
3. Calculate the waiting time for each of the process
10. Consider the following questions based on the banker’s algorithm:
Allocation Max Available
P0 ABC D ABC D ABC D
P1 001 2 001 2 152 0
P2 100 0 175 0
P3 135 4 235 6
P4 063 2 065 2
P5 001 4 065 6
(1) Define safety algorithm.
(2) What is the content of the matrix Need?
(3) Is the system in a safe state?
11. Discuss the threading issues which are considered with multithreaded programs
Answer the following based on banker’s algorithm
I. What is the content of NEED matrix?
II. Is the system in a safe state?
III. Which processes may cause deadlock if the system is not safe
i) If a request from process p1 arrives for (0, 4, 3, 1) can the
request be granted immediately? Justify.
12. Discuss in detail the critical section problem and also write the algorithm for
Readers- Writers Problem with semaphores
13. Discuss about the issues to be considered in the multithreaded program.
14. Is the current allocation in a safe state?
(i) Is it possible to have concurrency but not parallelism? Explain.
(ii) Consider a system consisting of four resources of the same type that are shared by three
processes, each of which needs at most two resources. Show that the system is deadlock free.
UNIT III - STORAGE MANAGEMENT
 PART – A
1. Why page are sizes always powers of 2?
2. Consider a logical address space of eight pages of 1024 words each, mapped onto a
physical memory of 32 frames.
3. How many bits are there in the logical address?
4. How many bits are there in the physical address?
5. What is address binding?
6. Difference between internal and external fragmentation
7. Define dynamic loading.
8. Define dynamic linking.
9. What are overlays? Compare swapping and overlays
10. List the strategies for managing free memory in kernel?
11. What is virtual memory? Mention its advantages.
12. Define Demand paging and write advantages.
13. What is the purpose of paging the page tables?
14. What do you mean by thrashing?
15. How do you limit the effects of thrashing?
16. What do mean by page fault?
17. Differentiate between Global and Local page replacement algorithms.
18. Define TLB.
19. Define Pre paging.
20. Define logical address and physical address.
21. What is the main function of the memory-management unit?
22. What is difference between demand paging n pure demand paging?
23. Define Copy-on-write.
24. Define swapping.
25. Define lazy swapper.
26. Define effective access time.
27. What is the basic approach of page replacement?
28. What is the various page replacement algorithms used for page replacement?
29. Differentiate between Global and Local page replacement algorithms.
30. What are the major problems to implement demandpaging?
31. Differentiate a page from a segment.
32. How do you limit the effects of thrashing?

PART-B
1. Describe the hierarchical paging technique for structuring page tables. (8)
 2. What is the cause for thrashing? How does the system detect thrashing? Once it
detects, what can the system do to eliminate this problem?
3. Write in detail about Segmentation.
4. Write in detail about Segmentation with Paging.
5. Explain the segmentation with paging implemented in OS/2 32-bit
IBM system. Describe the following algorithms:
a. First fit
b. Best Fit
c. Worst Fit
6. Explain how paging supports virtual memory. With a neat diagram
explain how logical address is translated into physical address.
7. Explain the principles of segmented and paging implemented in memory with a
diagram.
8. Explain the segmentation with paging implemented in MULTICS system.
9. Explain the various page table structures in detail.
10. Write short notes on LRU, FIFO and clock replacement strategies?
11. Explain any four page replacement algorithms in detail?
12. What is thrashing? Explain the working set model in detail. Given memory
partitions of 100KB, 500KB, 200KB, 300KB and 600KB(in order), how
would each of the first-fit, best-fit and worst-fit algorithms place processes
of212KB, 417KB, 12KB and 426KB(in order)? Which algorithm makes the
most efficient use of memory?
13. (i) Explain in briefly and compare, fixed and dynamic memory partitioning schemes.
(ii)Explain FIFO, optimal and LRU page replacement algorithms with an example
reference Strings. Mention the merits and demerits of each of the above algorithms.
14. Consider the following page reference string (MAY/JUNE 2012) (APR/MAY 2015)
1,2,3,4,2,1,5,6,2,1,3,7,6,3,2,1,3,6.
How many page faults would occur for the following replacement algorithms,
assuming one, two, three and four frames?
LRU replacement, FIFO replacement, Optimal replacement
15. (i) Consider the following page reference string: 2, 1, 0, 3, 4, 0, 0, 0, 2, 4, 2, 1, 0, 3, 2.
How many page faults would occur if the working set policy were used
with a window size of 4? Show when each page fault would occur clearly.
(ii)What is meant by thrashing? Discuss in detail.
16. Explain the concept of demand paging and the performance issue of short
process Explain the issue of demand paging
17. With a neat sketch, explain how logical address is translated into physical
address using paging mechanism?
18. Write short notes on Memory Mapped Files.

UNIT IV – STORAGE MANAGEMENT

PART – A
1. What is a file?
2. List the various file attributes.
3. What are the various file operations?
4. What are all the information’s associated with an open file?
5. What are the different accessing methods of a file?
6. What is Directory?
7. What are the operations that can be performed on a directory?
8. What are the most common schemes for defining the logical structure of a directory?
9. Define UFD and MFD.
10. What is a path name?
11. What are the various layers of a file system?
12. What are the structures used in file-system implementation?
13. What are the functions of virtual file system (VFS)?
14. Define seek time and latency time.
15. What are the allocation methods of a disk space?
16. What are the advantages of Contiguous allocation?
17. What are the drawbacks of contiguous allocation of disk space?
18. What are the disadvantages of linked allocation?
19. What are the advantages of Indexed allocation?
20. What is garbage collection?
21. Mention the objectives of File Management System.
22. What is the content of a typical file control block?
23. What are the two types of system directories?
24. What is meant by polling?
25. List the attributes of a file
26. Define buffering.
27. Define spooling.
28. Define rotational latency and disk bandwidth.
29. What are the various disk-scheduling algorithms?
30. What is the need for disk scheduling?
31. What is the use of boot block?
32. What is sector sparing?
33. What is seek time?
34. Write a brief note on RAID.
35. Write three basic functions which are provided by the hardware clocks and timers.
36. What are the advantages of Linked allocation?
37. How does DMA increase system concurrency?
38. Why rotational latency is usually not considered in disk scheduling?
39. What is HSM? Where it is used?
40. What is Relative block number?
PART-B
1. Explain the different disk scheduling algorithms with examples.
2. Explain and compare FCFS, SSTF, C-SCAN and C-LOOK disk scheduling
algorithms with examples.
3. Write short notes on disk management.
4. Write short notes on file system in Linux.
5. Write an elaborate note on RAID and RAID Levels.
6. Explain the services provided by Kernel I/O subsystem.
7. Consider the following I/O scenarios on a single-user PC.
8. A mouse used with a graphical user interface.
9. A tape drive on a multitasking operating system (assume no device pre allocation is
available)
10. A disk drive containing user files.
11. A graphics card with direct bus connection, accessible through memory-mapped
I/O For each of these I/O scenarios, would you design the operating system to
use buffering, Spooling, caching, or a combination? Would you use polled I/O,
or interruption driven I/O?
12. Write short notes on File types, File attributes, File operations
13. Explain the file allocation methods.
14. Explain the role of Access Matrix for protection in files.
15. Write in detail the security measures taken in file system? Write short notes on file
system mounting. Write in detail about the various file organizations Explain the
allocation of frames in detail.
16. Explain directory subsystem
17. Explain Linked File Allocation method.
18. Explain the issues in designing a file system.
19. Explain the various file directory structures.
20. (i) Explain the different file access methods in detail. (ii) Describe the two level and
acyclic graph schemes for defining the logical structure of a directory.
21. Explain the Linked list and indexed file allocation methods with neat diagram.
Mention their advantages and disadvantages.
22. What are the most common schemes for defining the
logical structure of a directory?
23. Write a brief note on the steps involved in DMA transfer.
24. Explain the data structures supported by kernel I/O system.
25. Write a brief note on tertiary storage devices.
26. Explain different directory implementation methods.
27. Why disk scheduling is necessary? Explain the different seek optimization techniques.
28. Explain about RAID structure in disk management with various RAID levels
of organization in detail.
29. Briefly discuss about the various directory structures.
30. Write short notes on free space management.

UNIT V - VIRTUAL MACHINES AND MOBILE OS

PART – A
1. What are Virtual Machines in Operating System?
2. How does a virtual machine interact with a physical computer?
3. What are the advantages of a virtual machine?
4. What are the characteristics of Virtual machine?
5. What are the types of virtual machine?
6. Define Virtualization in Operating System.
7. What is virtualization used for?
8. Why do companies use OS virtualization?
9. What are the objectives of Operating Systems?
10. What are the functions of operating system?
11. What are the components of operating system?
12. Define the concept of Mobile OS
13. List the types of Mobile OS
14. Give the features of Mobile OS
15. What are the components of a Mobile Operating System?

PART-B

1. Explain in detail about the Android architecture and its components

2. Explain the architecture of iOS. Discuss the media and service layers clearly.
3. Describe in detail about android file management .
4. Present an outline of types of Virtual machines. Explain in detail.
5. Outline the operating systems aspects of virtualization in the context of operating system
functions scheduling, I/O and memory management.
6. Explain various types of Virtual machines and their implementation in detail.
7. Compare iOS with Android OS.
8. Illustrate in detail about virtual machines, benefits and its history
9. Spell out virtualization and operating system components.
10. Explain in detail about building blocks of virtual machines.